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Stability Study on Hydroelectric Production Site Using Eigenvalues Analysis Method

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Journal of Energy and Power Engineering 2012年第6期6卷 940-948页

作者： Pedro Camilo de Oliveira e Silva Basile Kawkabani Sébastien Alligné Christophe Nicolet jean-jacques simond Francois Avellan Electrical Machinery Laboratory Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne CH-1015 Switzerland Laboratory for Hydraulic Machines Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne CH-1015 Switzerland Power Vision Engineering Sàrl Eeublens CH-1024 Switzerland

The eigenvalues analysis method is generally applied to synchronous machines by using d, q-components. This paper presents the application of this method on an equivalent model for the synchronous machine based on phase variables a, b, c instead of d, q-components. The advantages of this approach, essential for programs using phase variables as state variables, are presented. The application of this method to a complete hydroelectric production site including hydraulic components （pump-turbine, penstock, gallery, reservoir...） permits the study and analysis of the interactions between the hydraulic, electric and regulation parts of the system. Results coming from the proposed eigenvalues analysis method and the numerical simulations confirm the interest of the presented approach.

关键词： Hydraulic systems eigenvalues and eigenfunctions power systems transient analysis.

Antimony-based intermetallic compounds for lithium-ion and sodium-ion batteries:synthesis,construction and application

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Rare Metals 2017年第5期36卷 321-338页

作者： Wen Luo jean-jacques Gaumet Li-Qiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Laboratory of Chemistry and Physics:Multiscale Approach to Complex Environments(LCP-A2MC) University of LorraineMetz 57070France Department of Chemistry University of CaliforniaBerkeleyCalifornia 94720USA

The development of alternative electrode materials with high energy densities and power densities for batteries has been actively pursued to satisfy the power demands for electronic devices and hybrid electric vehicles. Recently, antimony（Sb）-based intermetallic compounds have attracted considerable research interests as new candidate anode materials for high-performance lithium-ion batteries（LIBs） and sodium-ion batteries（SIBs） due to their high theoretical capacity and suitable operating voltage. However, these intermetallic systems undergo large volume change during charge and discharge processes, which prohibits them from practical application. The rational construction of advanced anode with unique structures has been proved to be an effective approach to enhance its electrochemical performance. This review highlights the recent progress in improving and understanding the electrochemical performances of various Sb-based intermetallic compound anodes. The developments of synthesis and construction of Sb-based intermetallic compounds are systematically summarized. The electrochemical performances of various Sb-based intermetallic compound anodes are compared in its typical applications（LIBs or SIBs）.

关键词： Antimony Intermetallic compound Alloy Anode Sodium-ion battery Lithium-ion battery

Fractional order extremum seeking approach for maximum power point tracking of photovoltaic panels

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Frontiers in Energy 2015年第1期9卷 43-53页

作者： Ammar NECAIBIA Samir LADACI Abdelfatah CHAREF jean jacques LOISEAU Research Unit in Renewable Energies in the Saharan Medium CDEREPST URER-MS Adrar 01000 Algeria Department ofElectrical Engineering University of Skikda Skikda 21000 Algeria Department of Electronics Electrotechnics and Automatics NationalPolytechnic School of Constantine Constantine 25000 Algeria SP-LabLaboratory Department of Electronics University of Constantine 1Constantine 25000 Algeria SP-Lab Laboratory Department of Electronics University of Con-stantine 1 Constantine 25000 Algeria Research Institute in Communications and Cybernetics CNRS UMR6597 1 rue de la No~ 44321 Nantes France

Due to the high interest in renewable energy and diversity of research regarding photovoltaic （PV） array, a great research effort is focusing nowadays on solar power generation and its performance improvement under various weather conditions. In this paper, an integrated framework was proposed, which achieved both maximum power point tracking （MPPT） and minimum ripple signals. The proposed control scheme was based on extremum- seeking （ES） combined with fractional order systems （FOS）. This auto-tuning strategy was developed to maximize the PV panel output power through the regulation of the voltage input to the DC/DC converter in order to lead the PV system steady-state to a stable oscillation behavior around the maximum power point （MPP）. It is shown that fractional order operators can improve the plant dynamics with respect to time response and disturbance rejection. The effectiveness of the proposed controller scheme is illustrated with simulations using measured solar radiation data.

关键词： extremum seeking (ES) fractional ordercontrol (FOC) fractional calculus photovoltaic (PV)

Modelling and mathematical results arising from ferromagnetic problems

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Science China Mathematics 2012年第5期55卷 1053-1067页

作者： DESCLOUX jean FLUECK Michel RAPPAZ jacques Department of Mathematics Ecole Polytechnique Fdrale de Lausanne (EPFL)Lausanne 1015Switzerland

Abstract In this article, we investigate the equations of magnetostaties for a configuration where a ferromagnetic material occupies a bounded domain and is surrounded by vacuum. Furthermore, the ferromagnetic law takes the form B=μ0μr（｜H｜）Hi i.e., the magnetizing field H and the magnetic induction B are collinear, but the relative permeability μr is allowed to depend on the modulus of H. We prove the well-posedness of the magnetostatic problem under suitable convexity assumptions, and the convergence of several iterative methods, both for the original problem set in the Beppo-Levi space W1（R3）, and for a finite-dimensional approximation. The theoretical results are illustrated by numerical examples, which capture the known physical phenomena.

关键词： ferromagnetism nonlinear elliptic problems finite element methods optimisation algorithms

Heat Transfer Model with Two Heat Transfer Coefficients Along a M ultiperforated Plate-Application to Combustion Chamber Wall Cooling

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Journal of Thermal Science 2003年第4期12卷 363-366页

作者： Brice Petre Eva Dorignac jean jacques Vullierme Laboratoire d'Etudes Thermiques U.M.R C.N.R.S 6608-ENSMA BP 40109 86961 Futuroscope Chasseneuil Cedex FRANCELaboratoire d'Etudes Thermiques U.M.R C.N.R.S 6608-ENSMA BP 40109 86961 Futuroscope Chasseneuil Cedex FRANCELaboratoire d'Etudes Thermiques U.M.R C.N.R.S 6608-ENSMA BP 40109 86961 Futuroscope Chasseneuil Cedex FRANCE

Walls' cooling of aeronautic propeller combustion chamber is performed with the injection, through the combustion chamber wall, of a part of the air coming from compressors placed upstream. Measurements of the wall thermal fields are made by infrared thermography along the injection wall. This injection wall is pierced by 9 rows of 8 holes (α=90°) in staggered configuration (p/D=s/D=6). We propose a model using two heat transfer coefficients to represent the convective exchanges. The results are non-dimensioned and presented in comparison with the case without holes. The use of this model allows us to define 4 zones. Those 4 zones exist for the 5 blowing rates.

关键词： multiperforation cooling heat transfer coefficients infrared thermography.

Geological applications using geospatial standards-an example from OneGeology-Europe and GeoSciML

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International Journal of Digital Earth 2010年第S01期3卷 31-49页

作者： John Laxton jean-jacques Serrano Agnes Tellez-Arenas British Geological Survey Murchison HouseWest Main Rd.Edinburgh EH93LAUK BRGM 3 Avenue Claude-GuilleminBP 36009Orleans 45060France

The Geoscience Markup Language(GeoSciML)has been developed to enable the interchange of geoscience information,principally that portrayed on geological maps as well as boreholes.A GeoSciML testbed was developed both to test the implementation of the data model and its application in web *** OneGeology-Europe project aims to use the GeoSciML data model,and build on the experience of the GeoSciML testbed,in implementing a geoportal for a harmonised geological map of Europe at 1:1 million *** involves the integration of web services from 20 participating *** important objective of OneGeology-Europe is to contribute to Infrastructure for Spatial Information in the European Community(INSPIRE),both through the development of a geological data specification and the use of the INSPIRE technical *** and the OneGeology-Europe project are also steps towards incorporating geoscience data into a Digital *** the development of GeoSciML and the implementation of web services for GeoSciML and OneGeology-Europe,have followed a standards-based *** technical architecture comprises a geoportal providing access to a Catalogue Service for the Web for metadata describing both the data and services ***-Europe will provide bothWeb Map Services view andWeb Feature Services download services,which aim to be compliant with the INSPIRE implementing rules.

关键词： data exchange model web services spatial data standards INSPIRE digital earth geoinformatics geology

Soil Macrofaunal Communities are Heterogeneous in Heathlands with Different Grazing Intensity

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Pedosphere 2015年第4期25卷 524-533页

作者： jean-Franois PONGE Sandrine SALMON Amélie BENOIST jean-jacques GEOFFROY Muséum National d’Histoire Naturelle CNRS UMR 7179 4 avenue du Petit Chteau 91800 Brunoy (France) Muséum National d’Histoire Naturelle CNRS UMR 7204 4 avenue du Petit Chteau 91800 Brunoy (France)

Moderate grazing by cattle increases the heterogeneity of soil and vegetation. This has been suggested as an ecologically sustainable mean of managing natural environments endangered by tree encroachment, such as heathlands. Our study was performed to test the impact of grazing intensity on soil macroinvertebrate communities in heterogeneous landscapes in a private property eligible to the Natura 2000 European Network of Special Protection Areas within the Brenne Natural Regional Park （Indre, ~rance）. We sampled macroinvertebrates along a broken line crossing 5 different land-use types, from pasture to pine forest, passing through a besom heath （Erica scoparia） heathland at 3 levels of cattle pressure. We hypothesized that： i） litter-dwelling （mostly arthropods and mollusks） and soil-dwelling macroinvertebrates （mostly earthworms） would respond in an opposite manner to various grazing intensities, and ii） intermediate cattle pressure （pastured heath） would increase soil and community heterogeneity. The results supported the first hypothesis, which was explained by land-use impacts mediated by soil properties. However, our results supported only partly the second hypothesis since maximum dissimilarity （whether in the composition of soil macroinvertebrate communities or in soil features） was observed in only one out of the two pastured heaths where cattle pressure was intermediate.

关键词： besom heath cattle grazing heterogeneity land-use types soil macroinvertebrates

Recent Advances on Graphene Quantum Dots for Electrochemical Energy Storage Devices

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Energy & Environmental Materials 2022年第1期5卷 201-214页

作者： Noura Zahir Pierre Magri Wen Luo jean jacques Gaumet Philippe Pierrat CNRS L2CM UMR 7053 Universit e de Lorraine LCP-A2MC EA4632 Institut Jean Barriol Universit e de Lorraine State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technologywuhan 430070china

Graphene quantum dots(GQDs)which are nanofragments of graphene with an average size between 2 and 50 nm have attracted much attention due to their outstanding properties such as high conductivity,high surface area,and good solubility in various *** combine the quantum confinement and edges effects and the properties of ***,GQDs offers a broad range of applications in various fields(medicine,energy conversion,and energy storage devices).This review will present the recent research based on the introduction of GQDs in batteries,supercapacitors,and microsupercapacitors as electrodes materials or mixed with an active material as an auxiliary ***,discussed on selected examples,summarize the electrochemical performances and finally,challenges and perspectives are recalled for the subsequent optimization strategy of electrode *** review is expected to appeal a broad interest on functional GQDs materials and promote the further development of high-performance energy storage device.

关键词： energy storage graphene quantum dots lithium ion batteries sodium ion batteries supercapacitor

Effects of aging on the microstructures and mechanical properties of extruded AM50+xCa magnesium alloys

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Rare Metals 2006年第4期25卷 377-381页

作者： WANG Qudong PENG Jianguo Suéry Michel jean-jacques Blandin National Engineering Research Centre of Light Alloys Net Forming School of Materials Science and Engineering Shanghai Jiaotong UniversityShanghai 200030 China Institute National Polytechnique de Grenoble （INPG） Génie Physique et Mécanique des Matériaux （GPM2） UMR CNRS 5010 ENSPG BP46 38402 Saint-Martin d＇Héres Cedex France

The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x=0, 1, 2 wt.%） were studied. The results indicated the secondary phase Mgl7Al12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50 ＋ xCa al- loys increased initially to its peak, and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature, the hardness of the AM50 ＋ 2Ca ahoy decreased, whereas the hardness of AM50 and AM50 ＋ 1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50 ＋ 1Ca alloys increased after aging treatment for the precipitation of Mg17Al12 phase, which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature, their tensile strengths increased. For AM50 ＋ 2Ca alloy, the tensile strength declined after aging at 150℃ and 175℃, while it increased slightly at 200℃. The ductility of AM50 ＋ xCa alloys （x = 0, 1, 2 wt.%） declined after aging treatment.

关键词： AM50 + xCa alloys aging extrusion mechanical properties